Conventional animal feeders include traditional troughs, feed bowls, etc. Such feeders are generally designed to provide a single meal for one or more animals, and typically restocked manually prior to the next meal. Some automation has been added to such feeders in prior art. One of the simplest being gravity feed: where food is replenished from a storage container by the action of gravity; moving food from the container into spaces left in the food bowl.
Gravity feeders typically use dry food, since moist food tends to spoil after a relatively short time. The problem of spoiling has been partially solved in prior art with feeders having a rotating lid. A portion of the lid is cut away so that a fresh meal is exposed each time the lid rotates. Some variants include refrigerated or ice cooled chambers to keep moist food fresh. The main disadvantage of such systems is that the number of meals is limited, since relatively few food chambers can be accommodated in a reasonable overall size. The construction of these feeders also makes replenishing and cleaning a relatively time consuming task compared to gravity feeders. Similarly, prior art includes refrigerated containers that extrude moist food into a bowl periodically using a drive piston, activated by a timer.
Gravity feeders have also incorporated some automation in prior art, such as employing feed valves to deliver food according to a timer or by physical actuation (learned by the animal). Some other variants supply a measured amount of food each serving. All such methods are quite effective in controlling food intake for solitary animals, but if more than one animal uses the feeder, it is not possible to determine how much each animal intakes. Furthermore, any excess intake by one animal will be at the expense the other animals sharing the feeder.
In a different class of automatic feeder, prior art exists that uses electronic tags to identify each individual animal; in one example electronic tags are fitted to cows to uniquely identify them. The tag is detected at the feeding station and food is dispensed on an individual basis into a trough. However this approach can not guarantee that other cows will not steal the food once it has been dispensed.
Similarly, implanting tags in the body of animals has been proposed in prior art as a means of identification for feeding purposes. In one example, the tag and feeder communicate by an electromagnetic wave traveling between them and the passive tag is powered by the incident electromagnetic wave. In this example, the tag stores feeding information relating to the animal and the feeder dispenses food, based on the presence of the tag and the animal's historical feeding schedule. The system is intended to address the problem of feeding an animal in the owner's absence, and attempts to prevent spoiling/wasting food by dispensing when the animal is absent. However this approach does not address this issue of access prevention for unauthorized animals or regulating the food intake of multiple animals using the same feeder, on an individual basis. In addition using an implanted tag would require an impractically high level of transmitted RF power to power the passive tags in practice and which may also desensitize the receiver.